This invention relates generally to low cost electronic packaging for use in rugged environments and more particularly to military ordnance applications.
Substrates upon which electronic components are mounted and electrically connected have been known and used for some time. It is often useful to connect two or more substrates to form a module to perform functions that cannot be performed by one substrate alone.
One application where tow or more interconnected substrates are needed is in ordnance projectiles. Designing interconnected substrates for these projectiles presents unique problems. First, such projectiles undergo rapid acceleration, thereby placing great stress on any interconnection between substrates. Substrates interconnected by use of additional parts, such as pins, wires or connectors may come loose in the rugged environment of an ordnance projectile. Thus, there is a need for substrates which can be formed into an electronic module having high inherent mechanical strength and electrical and mechanical connection reliability. Second, since ordnance projectiles are small, any set of interconnected substrates must be capable of assuming a variety of shapes to conform to the limited space inside any particular projectile. Also, any set of substrates used in a projectile should have a low manufacturing cost and be compatible with existing electronic circuitry fabrication technologies.
It is also desirable to permit access to the volume along the axis of the projectile for such uses as rotary setting mechanisms, fluidic power supplies, or explosive trains. EMI shielding, when necessary to a particular circuit, is likewise an important concern in projectile component design. Thus, an interconnected substrate module should be constructed to accommodate these concerns.